ISBN : 978-93-85073-24-3 According to the BCS, the dissolution rate is the limiting factor for the absorption of class II and IV drugs. Currently, 40% of the NCE fall in these two classes. Such molecules provide potential challenges to the formulation scientist. Their poor water solubility almost inevitably leads to low oral bioavailability from conventional dose forms. Poor aqueous solubility is an industry wide issue, especially for pharmaceutical scientists in drug discovery and drug development. A poorly water soluble drug is usually associated with poor absorption and bioavailability upon oral administration [133]. Although a certain degree of hydrophobicity is necessary for a drug molecule to cross the cell membrane easily [134], the overall rate of absorption is dictated by the time required for the dosage form to release its contents, and for the drug to dissolve in the GI fluid [135]. The water solubility of ‘poorly soluble’ drugs is usually less than 100 µg/mL [136]. A further parameter useful for identifying ‘poorly soluble’ drugs is the dose:solubility ratio of the drug. The dose:solubility ratio is defined as the volume of GI fluids necessary to dissolve the administered dose. When this volume exceeds the volume of fluids available, one may anticipate incomplete bioavailability from solid oral dosage forms. In fact, developing dissolution test methods for poorly water-soluble drug products has been an important task to formulation scientists. Problems encountered with poorly water-soluble drug product include a low extent of drug release and a slow release rate. General strategies to enhance their dissolution patterns rely upon either changing the dissolution medium pH, or adding solubilizers such as surfactants cyclodextrin derivatives into a dissolution medium [137-145]. Polymeric Surfactant Detergents belongs to a class of compounds called surfactants, which are surface active agents that reduce interfacial surface tension in mixture (i.e., oil and water) by adsorbing to interfaces [146]. The ability of a detergent to participate in a specific biological/biochemical function is related to its structure; the polar hydrophilic portion of the detergents molecule is referred to as the “hydrophilic head group” while the nonpolar hydrophobic, portion is referred to as the “tail”. Surfactants play a major role in the absorption of drugs in the body [147-148]. In the late 1960s, micelles drew much 12
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